Dry reforming of methane to syngas using CO2 was performed in a solar-driven milli-scale reactor, which converts solar energy to chemical energy. The process aims to upgrade the energy content of the feed stream using sustainable energy. The effect of mean residence time, temperature and CO2:CH4 ratio on conversion and energy efficiency were tested in the reactor. The experiment demonstrates syngas production by dry reforming reaction in a milli-scale reactor Using a simple nickel catalyst, the reactor achieved 10% solar-to-chemical energy conversion efficiency at 0.028s mean residence time, 1000°C temperature and 1:1 CO2:CH4 ratio. If a recuperator were added to recover sensible heat of the product gases, this concept shows a possibility to achieve higher solar-driven energy conversion efficiency of thermal to chemical energy. Finally, this work lays the framework for the future design of a microreactor.